Re: Autonomy: How Did You Guys Do It?
 

Wow! I've never done this before! I attempted to "track" still objects in various still pictures - a ball, a stick, a box - all color and at different lightings but I never was able to do this successfully. My main question is not how to apply an hsl threshold or clean up the photo after a threshold, but what to do with all that data I get using the stat VI's and such - I'm using labview. What does it all mean? and what on earth am i supposed to do with it to make my program know that it's looking at the target? thanks

Re: Autonomy: How Did You Guys Do It?
 

We used light sensors for line tracking, encoders for auto-correction, and an encoder on the arm for height determination. It's never failed. It's also kind of showy since instead of placing the tube it throws it down onto the peg.

Re: Autonomy: How Did You Guys Do It?
 

I used a gyro on the base to keep it straight, an encoder for distance, and a second gyro to determine arm angle. I'm hoping to rig up another encoder so as to have two straight-correcting sensors and average the two corrections, or use one as a safety net in case one malfunctions.

Re: Autonomy: How Did You Guys Do It?
 

I was told by several older members and mentors to abandon the use of sensors altogether because of our history with sensors. Essentially, don't use them because we've never used them. What I thought was hilarious about this discussion was that half of these guys were mechanical, and couldn't tell between a potentiometer and an encoder.
</rant>

The autonomous program I've been using in San Diego and Los Angeles was dead reckoning with timers. It worked about 70% of the time. Aim for middle peg, score on left peg.

I plan to have a basic autonomous program using the encoders and gyro. This will at least go straight. I will test and implement this this week in Utah. Another variation of this program will attempt to put up two tubes. But this is a long shot...

If we make it to STL, I want to mount an ultrasonic sensor for distance sensing.

Sensors on James Bot:
Potentiometer on arm shoulder
Encoders on drivetrain
Gyro on drivetrain
CAN Bus Current Sensors(Used in our roller claw to sense tubes)

I've had KOP light sensors mounted, but 2/3 were mangled during practice on concrete, the other one doesn't seem to calibrate. I have abandoned these.

Re: Autonomy: How Did You Guys Do It?
 

Man, that is some questionable advice!

We used encoders on all 4 wheels, a pot on the arm and an ultrasonic sensor on the front and rear. Our bot simple rolled forward X feet (measured by the encoders), raised the arm to the 9' height (measured by the pot), released the ubertube and backed off some. We used the ultrasonic sensors to align for minibot deployment.

Reliable sensors are a HUGE advantage in autonomous mode and can be used to automate certain movements in teleop mode (like releasing a tube and lowering an arm in perfect sequence). If you understand them, program them correctly and test them thoroughly - USE THE SENSORS!

HTH

Re: Autonomy: How Did You Guys Do It?
 

I'm less interested in how they did it, instead what I want to know but is kind of mishaps occured during autonomous period?

One match, our robot drove straight backward and rammed another, pushing them in to their scoring zone, giving my team a red card, instead of just line sensing. Sooo unexpected. :eek:

Re: Autonomy: How Did You Guys Do It?
 

We Use two electric eyes for line tracking and an utrasonic distance sensor for distance we got from Pololu.com. The distance sensor is awesome, with in +/- an inch. You have to correct a little for coasting when the motors are put to zero speed. Our arm is pneumatic so it just goes to the top position which is good for either the middle or left and right pegs. We also have two distances which are selected by the driver by moving the right hand joystick throttle either fully up or fully down. WQe need to be closer to the wall when we stop and hang the tube if we play the middle Y tape position.

At the correct distance we stop and let go of the uber tube and lower the arm. Then back up sending equal speed signals to the motors at 13 seconds in we lower the arm.

At our first district we never missed a top level uber tube score. We did not back up there and almost dropped the tube because when the arm fully retracted we hit the middle peg.

So we added the backing up before district competition #2. We had a couple of misses there because the the joy stick was set for the middle Y tape positon and we got too close and the arm joint caught on the middle peg and shook off the tube.

At MSC we did not miss except for when an partner robot veered into us and one other time when at end of day Friday match the tape was screwed up and the robot veered off. Our driver now check the tape on the floor before every match.

Re: Autonomy: How Did You Guys Do It?
 

I seen almost the same thing in the Niles, MI district Finals match. It happened in the last finals match. The other alliance called a time out and when the match started a robot went backwards al the way into our safe zone. I felt sorry for them and especially the programmer. (But for the grace of GOD it could have been me)

We did not know what they were working on in the time out but I assume the autonimous program for that robot was a part of it.

At MSC one of of our alliance partners did not use the tape but instead lined up right beside our robot. They veered into ours and knocked it off the tape and it missed. I seen a lot of the teams doing this there ( I don't know how they were programed) and I was not impressed with it. Some worked well but most missed and many stopped an alliance partner from scoring.

Re: Autonomy: How Did You Guys Do It?
 

- 1 encoder on SuperShifting transmissions
- Transmissions in low gear
- 1 Gyro with semi-aggressive PID control for "drive straight"

1. Finely tune the encoder distances
2. DO NOT turn the robot on until it is set down. If they gyro init's before it's set down, then it's game over
3. Push the bot backwards a little so that the chains are pre-tensioned. This should help alleviate drive straight problems from lurching
4. Ramp up the speed rather than going 100% full blast
5. Dead-reckon to the peg

Once it was tuned, we had 9 straight auto-modes score.